But in a twist, Holmes' defence counsel Conan Rae asked that his client be re-arraigned. After the charge was again put to Holmes, he pleaded guilty and applied for bail ahead of sentencing next month.

Crown lawyer Laura Ivers said that if the court was to grant continuing bail, the prosecution would be seeking a number of "additional requirements".

She told the court that one was that Holmes was not to leave Northern Ireland. A further condition was that he surrenders his passport before being released.

She added the prosecution was opposed to a defence application for Holmes' bail-signing conditions at Musgrave PSNI station to be relaxed from three times a week to twice weekly.

However, Mr Rae, defending, said that the police officer in charge of the case did not oppose the relaxation of his client's signing conditions and added: "I understand the Public Prosecution Service takes another view in respect of that." The defence barrister also pointed out Holmes was already the subject of a 10pm-7am curfew.

Judge Fowler QC ordered that Holmes must not leave Northern Ireland and that he must also surrender his passport before being released on bail.

"I will relax his signing conditions from three times a week to twice a week," he added.

Holmes will be sentenced on May 19 following the completion of a pre-sentence report by the Probation Service.

No details were given in court yesterday about the nature of the charges.

However, when Holmes first appeared at Ards Magistrates Court last year, a judge was told that the burglary was not discovered until May 17, two days after it happened.

Lady Rose Lauritzen, daughter of the late Lady Mairi Bury, discovered that between £35,000 and £40,000 worth of her jewellery had been taken from her bedroom.

Despite the property having been given to the National Trust in the 1970s, members of the Londonderry family continued to live there in private quarters.

The court heard CCTV footage showed a man fitting Holmes' description "wandering" around corridors in a private area of the estate wearing a National Trust hat at around 2pm.

A constable told the magistrates hearing at the time that it was believed Holmes - who has 110 previous convictions - had found a key for Lady Rose's bedroom.

The court also heard that the defendant was arrested by police at Belfast International Airport, where he was about to board a flight bound for Amsterdam, carrying £1,700 in cash.

None of the stolen jewellery has yet been recovered.

Mount Stewart is an 18th century house and garden on the east shore of Strangford Lough near Greyabbey.

Famous for its beautiful gardens, it was the Irish seat of the Vane-Tempest-Stewart family, the former marquesses of Londonderry.

The family played a leading role in British and Irish social and political life.

Prince Charles, who is president of the National Trust, visited Mount Stewart several days after the burglary during a trip to Northern Ireland in May last year.

The trust property had undergone a dramatic three-year restoration programme before the visit.